lithophane image on ebay
examples above from Helen's Lithophane collection
I never heard of lithophanes before! I came across these unique curiosities while surfing for interesting old Japanese teacups. There is a whole page of porcelain dragonware teacups on ebay with lithophanes in the bottom, little pictures that are only visible when you hold them up to the light. Helen of "Helen's Lithophanes" explains what they are on her website homepage. Click on the flags at the bottom to view lithophanes from Japan, Germany, France, England, Hungary, Sweden, and America. Note: they aren't always found in teacups.
Here's Helen's Japanese page: LINK
Nick's collection of royal and historical portraits. LINK
By the way, I am currently painting an "ema" (wooden votive/prayer plaque) for an upcoming benefit art auction for Japan (April 3). More about that soon!